The Pfizer vaccine is one of the new mRNA types of SARS-Cov-2 vaccines. It is 95% effective in clinical trials and is given in two shots 21 days apart injected into the upper arm's muscle.
It does not contain preservatives, eggs, or latex.
It does contain polyethylene glycol, which causes allergic reactions in a tiny percentage of recipients.
Side effects that are not an allergic reaction include pain, swelling, and redness in the arm you got the shot in and chills, tiredness, and headaches throughout the rest of your body. Side effects usually go away in a few days.
The Moderna vaccine is quite similar to the Pfizer vaccine in most respects. It is given in two shots 28 days apart.
The polyethylene glycol base used for both vaccines is also used for many other common vaccines. Allergic reactions are rare, but they do happen, usually within four hours of receiving the vaccine.
There are presently more than 240 COVID-19 vaccines in development worldwide. Health officials expect that new vaccines will help combat the latest variations of COVID-19 that are cropping up and spreading fast.
Many of the new vaccines don't require super low-temperature storage, eliminating the logistical problems of existing vaccines —Pfizer's vaccine must be stored -70 and Moderna's at -15.
Several new vaccines in the US will be available later this year.
The University of Washington has a one in trials. It delivers proteins from SARS-CoV-2 that fuse with human cells. Neil King, a biochemist at the Institute for Protein Design, says this method has the potential to be ten times more effective than vaccines using whole, natural spike protein.
Johnson & Johnson has a one-shot vaccine that is 66% effective in trials. It will be available in March.